Although small, passive samplers to determine exposure to gases and vapors are commercially available, small samplers for particles have not yet been developed. Area samplers for particles often require 110 volt power; personal samplers require belt-worn pumps and tubing that winds around the worker to reach the breathing-zone. If a small, inexpensive sampler for particles can be developed that is similar to the passive samplers used to monitor gases and vapors, our ability to monitor particle exposures will improve substantially. Further, a particle monitor should ideally determine long-term exposures as chronic exposures cause chronic obstructive pulmonary disease. Thus, the objective of this research is to develop a miniature, passive aerosol sampler that will reliably estimate long-term average concentrations and size distributions. The prototype passive sampler described here is about the size of a dime and costs only a few dollars. It collects particles by gravity, diffusion, and convection. After exposure the sampler is capped, then sent to the laboratory for examination with a scanning electron microscope (SEM). The concentration and size distribution of particles in the air during sampling are determined from the SEM data using a model for particle deposition velocity. Analyses can be automated to keep costs low. This pilot study will evaluate the operation of a prototype passive sampler in a wind tunnel under controlled conditions. Limited field trials will be conducted at an industrial site, where the performance of passive and conventional samplers can be compared. This work, if successful, will lead to an RO1 proposal to evaluate passive particle samplers more thoroughly.